This is not exactly true. AFAIK you need to set it up correctly. But…
- What driver did you have installed at first?
- What happened when you connected the external monitor with your old (driver) setup?
- Did you search the forum for issues related to your specific card and nvidia?
- Check what the Xorg.0.log reports on boot and with plugging ext monitor
I would suggest to start clean,
- uninstall VGA driver with mhwd,
- clean blacklists from
- Reboot (before grub execution unplug external monitor)
- If X fails
- go to TTY and install bumblebee or plain nvidia (since you 'll have it on power as workstation)
- Restart DM (ie. sudo systemctl restart lightdm)
- Login and connect external monitor
- If no Display Connect success or Popup , run
xrandrto check if ext-mon is recognized
Then report any results to continue troubleshooting.
Nvidia and bumblebee is a PITA, at least to me, so, proceed with care.